This invention relates generally to a face shield structure for use in conjunction with an open face helmet.
A great many operators of open cockpit vehicles, in particular operators of motorcycles, wear helmets for their protection and because of laws passed by the various governmental levels. In order to protect riders from dangers encountered by and the possibility of trash, debris, or the like striking the face, many different types of face shields have been designed and manufactured. Such face shields generally include a curved, transparent member which is rigidly affixed to a helmet with the bottom edge open so that the helmet and attached face shield can be placed over the head of the wearer.
It is well known that the transparent member of the face shield becomes scratched or soiled so as to prevent clear vision. Attempts to clean the transparent member usually result in further scratching of the durable plastic or similar material of which the shields are typically composed. Restricted vision poses obvious hazards to operators of high speed vehicles or other powerful machinery. Further interference with the wearer's vision is caused by changes in the lighting conditions of the surrounding environment. In dim lighting a clear transparent panel should be used to allow all possible light to reach the wearer's eyes. In bright sunlight a tinted panel would be advantageous to filter out excessive glare. Also the face shield often becomes fogged by condensation of the wearer's breath on the inside of the transparent portion of the shield. Further, face shields which generally overlay the wearer's face can cause discomfort by unduly restricting the air circulation when the wearer is moving at a slow speed or air velocity relative to the helmet is slowed or stopped. Many attempts have been made to solve each of these problems separately; but, none of the previous attempts have been totally successful in solving all of these problems at the same time.
Detachable shields have been used so that they may be replaced when they become scratched or changed when the light conditions dictate. However, replacement of the entire shield is expensive and wasteful when the shield is composed of material of sufficient thickness to provide durable shielding from high velocity air, debris or similar matter or protection in the event of an accident. Further the prior art detachable shields lock into position so as to do nothing to overcome the problems of fogging and restricted air circulation. Inexpensive thin plastic removable coverings, which could be stretched or attached over the surface of thicker expensive permanent shield have been devised and used with only limited success. Moisture, oil, dirt, sand, and grit becomes trapped between the thin covering and the permanent shield. Entrapped grit causes scratching of the permanent shield when the two shields are vibrated relative to each other by buffeting winds. This mandates frequent and expensive permanent shield replacement.
Face shields designed to be attached to helmets so that they may be pivoted into and out of a shielding position have been used to alleviate some of the air circulation problems associated with low speed use. However, freely pivoting face shields, which allow uncovering of the wearer's face, are often unpredictably and violently pivoted upwardly by high velocity air currents. This exposes the wearer's face to flying debris and also dangerously jerks back the wearer's head and neck, possibly causing severe injury. Up to the present time such violent pivoting was prevented by the application of devices for rigidly locking the face shield in a downward, shielding position. Those prior art locking devices which could be engaged or disengaged while the helmet was being worn, required the wearer to disengage the devices with one hand while pivoting the shield upwardly with the other. Alternatively, using a single hand, the wearer could both dissengage and pivot the shield, only with much physical effort and by positioning that one hand in awkward and possibly dangerous locations behind the head or in the path of view. Such devices are of limited use to operators of high speed or unstable vehicles, such as motorcycles, which require at a minimum one hand on the controls and clear unobstructed vision at all times. It is with these problems in mind that the replaceable transparent panel and the automatic restraining and releasing detent mechanism in this invention has been developed.